1. Field of Invention:
The invention relates to seals and, more particularly, is directed towards a seal for preventing fluid flow between two mating surfaces.
2. Description of the Prior Art:
A sealing line or seal band is an unbroken and continuous line or area of contact between a seal and its mating surfaces which effectively stops fluid migration from a pressurized space to one of lower pressure. Anything that interrupts the continuous and unbroken line or band will cause or increase leakage. Because the seal line must be continuous and unbroken, the ideal seal will tolerate a wide range of variables which affect that continuity. For many sealing applications where conditions of temperature, pressure, fluid, and geometry permit its use, the O-ring is often an excellent choice. Because of its round cross section, the O-ring readily conforms to common geometric shapes found in fluid power application, and quickly forms the seal line or band. However, O-rings suffer from the disadvantage that the flash point or a separation point on the mold from which the O-ring is made constitutes an imperfection which provides only a limited degree of sealing in certain instances. Another disadvantage is the necessity of providing a lead angle on the mating member to be sealed in order to prevent O-ring damage upon engagement or to reduce the engagement force encountered in assembly.
Lip seals or U-rings are widely used in both pneumatic and hydraulic applications. However, lip seals suffer from the disadvantage that they relax in a short period of time after installation. Although continued application of fluid pressure will resulting resealing of the lip seal, the initial application of fluid pressure will result in some leakage due to this relaxation or set.
A need has arisen for an improved seal having a cross-sectional profile which provides increased sealing characteristics while requiring less radial distance than prior art seals.